The present invention relates to a rotary screw compressor having a casing defining a working space, in which a pair of rotors is mounted with the rotor axes in a horizontal plane, said casing having an inlet channel and having means for injecting a liquid into said working space, said working space having an inlet port communicating with said inlet channel through an inlet chamber, the connection between said inlet channel and said inlet chamber being located below said horizontal plane.
Rotary screw compressors are well known and widely used for producing compressed air or in refrigeration systems, and their general structure and working principle therefore need not to be explained.
U.S. Pat. No. 4,762,469 discloses a compressor of the type specified above. A horizontally mounted compressor having the inlet channel coming from below offers in many cases advantageous solutions how to design the system in which the compressor forms a part. A compressor in a refrigeration or heat pump system can for example be mounted on the top of the evaporator with the downwardly directed inlet flange of the compressor directly connected to the upwardly directed outlet flange of the evaporator. U.S. Pat. No. 2,963,884 discloses a similar type of compressor, although intended for air compression and not being liquid-injected.
With a compressor so mounted, however, a certain problem can arise. If the compressor is of the type having means for injecting a liquid, e.g. oil into the working space for sealing, lubricating and cooling purposes, the oil by gravity might flow down into the inlet channel. If the inlet channel is connected to a lower located evaporator, the evaporator will be filled with oil and its efficiency negatively affected. In case the compressor is provided with a slide valve for regulating the capacity this problem will be considerably accentuated at part load, since with the recirculation of working fluid a large quantity of the oil will be returned to the inlet port.
The object of the present invention is to avoid that liquid injected into the compressor will flow back to the inlet channel.
According to the invention this has been attained in that said inlet chamber is provided with partition wall means collecting any liquid leading out from the working space through the inlet port and preventing it from reaching the inlet channel.
Advantageous embodiments of the invention are specified in the dependent claims.
The invention is explained more in detail by the following description of a preferred embodiment thereof and with reference to the accompanying drawings.